CN116825919A - LED epitaxial wafer, preparation method thereof and LED - Google Patents

Abstract

The invention discloses a light-emitting diode epitaxial wafer and a preparation method thereof, and an LED, wherein the light-emitting diode epitaxial wafer comprises a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a P-type insertion layer, an electron blocking layer and a P-type GaN layer which are sequentially laminated on the substrate; the P-type insertion layer comprises an AlGaN layer, an Mg-doped AlGaN layer and an Mg-doped GaN layer which are sequentially laminated on the multiple quantum well layer; the Al component content in the AlGaN layer is higher than that in the Mg-doped AlGaN layer, and the Mg component content in the Mg-doped AlGaN layer is lower than that in the Mg-doped GaN layer; the growth temperature of the P-type insertion layer is lower than that of the multiple quantum well layer. The LED epitaxial wafer provided by the invention can effectively reduce the influence of the high-temperature P-type covering layer on the multiple quantum well layer and improve the luminous efficiency of the GaN-based LED.

Description

LED epitaxial wafer, preparation method thereof and LED

Technical Field

The invention relates to the technical field of photoelectricity, in particular to a light-emitting diode epitaxial wafer, a preparation method thereof and an LED.

Background

After the growth of the GaN-based LED epitaxial quantum well active layer is finished, a P-type covering layer is continuously grown, the P-type covering layer comprises an electron blocking layer and a P-type GaN layer, the higher growth temperature increases the metal atom diffusion capacity of the growth surface, the growth of a gallium nitride surface can be promoted, and V-bits can be filled, so that the flat surface morphology is obtained. The growth temperature of the P-type coating layer is too low, the growth quality is not high, the V-bits cannot be filled up, and the surface roughness is increased. To improve the growth quality of the P-type cladding layer to obtain a flat surface morphology, a higher growth temperature is required to be maintained to reduce carbon impurities, and the atomic surface mobility is improved to promote the lateral growth rate of GaN, so that a better defect cladding effect is achieved.

The growth temperature of the high quality P-type cladding layer is typically around 1000 ℃, while the growth temperature of the multiple quantum well layer (MQW), i.e. the active layer, of the GaN-based LED is typically around 800 ℃. The growth temperature of the high quality P-type cladding layer is significantly higher than that of the active layer, which can produce some side effects. Too high a temperature may have an effect on the In content and distribution In the quantum well of the latter couple of active layers, causing them to decompose and segregate. Too high growth temperature of the P-type GaN coating layer can aggravate fluctuation of indium components in the quantum well structure, and reduce the luminous efficiency of the GaN-based LED. The excessive epitaxial growth temperature of the P-type layer can cause the deterioration of the structure, the photoelectric characteristics and the like of the multi-quantum well. Excessive epitaxial growth temperature aggravates the fluctuation of indium distribution in the multiple quantum well structure, causes the formation of a plurality of non-radiative recombination centers, widens the PL peak, reduces the luminous intensity, and finally worsens the performance of the green LED device.

Since the electron and hole concentrations in GaN-based LEDs are scattered with non-uniform characteristics, the actual values of electron concentrations significantly exceed hole concentrations. At the same time, the actual mobility of electrons also exceeds that of holes. This causes electron hole recombination in GaN-based LEDs, focusing on the quantum well layers close to the P-type cladding layers. The growth position of the P-type coating layer is positioned behind the active layer, and the excessively high growth temperature has the greatest influence on the quantum well layer close to the P-type coating layer, so that the luminous efficiency of the LED is greatly influenced.

For GaN-based LED structures with larger V-bits structures, it is particularly important to grow high-quality P-type cladding layers, which can effectively cover the V-bits and reduce the roughness of the device surface. But the high temperature of the P-type cladding layer has a negative impact on the quantum well. How to reduce the influence of the high-temperature P-type coating layer on the multiple quantum well layer and improve the antistatic capability and luminous efficiency of the GaN-based LED device is a problem to be solved in the field.

Disclosure of Invention

The invention aims to solve the technical problem of providing the light-emitting diode epitaxial wafer, which can effectively reduce the influence of a high-temperature P-type coating layer on a multi-quantum well layer and improve the light-emitting efficiency of a GaN-based light-emitting diode.

The invention also aims to provide a preparation method of the light-emitting diode epitaxial wafer, which has simple process and can stably prepare the light-emitting diode epitaxial wafer with good luminous efficiency.

In order to solve the technical problems, the invention provides a light-emitting diode epitaxial wafer, which comprises a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a P-type insertion layer, an electron blocking layer and a P-type GaN layer which are sequentially laminated on the substrate;

the P-type insertion layer comprises an AlGaN layer, an Mg-doped AlGaN layer and an Mg-doped GaN layer which are sequentially laminated on the multiple quantum well layer;

the Al component content in the AlGaN layer is higher than that in the Mg-doped AlGaN layer, and the Mg component content in the Mg-doped AlGaN layer is lower than that in the Mg-doped GaN layer;

the growth temperature of the P-type insertion layer is lower than that of the multiple quantum well layer.

In one embodiment, the Al doping concentration in the AlGaN layer is 3×10 ⁸ atoms/cm ³ ～7×10 ⁸ atoms/cm ³ ；

The Al doping concentration in the Mg-doped AlGaN layer is 1.5X10 ⁸ atoms/cm ³ ～3.5×10 ⁸ atoms/cm ³ 。

In one embodiment, the Mg doping concentration in the Mg doped AlGaN layer is 2×10 ¹⁹ atoms/cm ³ ～5×10 ²⁰ atoms/cm ³ ；

The Mg doping concentration in the Mg-doped GaN layer is 5 multiplied by 10 ²⁰ atoms/cm ³ ～8×10 ²¹ atoms/cm ³ 。

In one embodiment, the Al doping concentration in the AlGaN layer gradually decreases from the multiple quantum well layer to a direction away from the multiple quantum well layer.

In one embodiment, the Mg doping concentration in the Mg doped AlGaN layer gradually increases, and gradually decreases from the AlGaN layer in a direction away from the AlGaN layer.

In one embodiment, the AlGaN layer has a thickness of 5nm to 50nm;

the thickness of the Mg doped AlGaN layer is 30 nm-100 nm;

the thickness of the Mg doped GaN layer is 20 nm-100 nm.

In one embodiment, the growth temperature of the P-type insertion layer is 750 ℃ to 800 ℃.

In one embodiment, during the growth process of the AlGaN layer, the Al source inlet flow rate is gradually changed from 200scc to 250scc to 50scc to 100sccm;

in the growth process of the Mg-doped AlGaN layer, the inflow flow of the Mg source is gradually changed from 0scc to 50scc to 1000scc to 1500sccm.

In order to solve the problems, the invention also provides a preparation method of the light-emitting diode epitaxial wafer, which comprises the following steps:

s1, preparing a substrate;

s2, sequentially depositing a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a P-type insertion layer, an electron blocking layer and a P-type GaN layer on the substrate;

the P-type insertion layer comprises an AlGaN layer, an Mg-doped AlGaN layer and an Mg-doped GaN layer which are sequentially laminated on the multiple quantum well layer;

the Al component content in the AlGaN layer is higher than that in the Mg-doped AlGaN layer, and the Mg component content in the Mg-doped AlGaN layer is lower than that in the Mg-doped GaN layer;

the growth temperature of the P-type insertion layer is lower than that of the multiple quantum well layer.

Correspondingly, the invention further provides an LED, and the LED comprises the LED epitaxial wafer.

The implementation of the invention has the following beneficial effects:

the invention provides a light-emitting diode epitaxial wafer, which is characterized in that a P-type insertion layer with a specific structure is inserted between a multiple quantum well layer and an electron blocking layer, the light-emitting diode epitaxial wafer comprises a first electron blocking layer, a hole compensation layer and a second electron blocking layer which are sequentially laminated on the multiple quantum well layer, and the P-type insertion layer comprises an AlGaN layer, an Mg-doped AlGaN layer and an Mg-doped GaN layer which are sequentially laminated on the multiple quantum well layer; the Al component content in the AlGaN layer is higher than that in the Mg-doped AlGaN layer, and the Mg component content in the Mg-doped AlGaN layer is lower than that in the Mg-doped GaN layer; the growth temperature of the P-type insertion layer is lower than that of the multiple quantum well layer.

According to the invention, the doping concentration of Mg in the P-type insertion layer is changed from low to high, so that the tunnel width of a PN junction generated by the GaN-based LED is wider, and the probability of zener breakdown is greatly reduced. PN junction with lower doping and wider tunnel width is easy to generate avalanche breakdown and has higher breakdown voltage, the reverse voltage of the GaN-based LED is obviously increased, and the luminous efficiency is obviously improved.

In addition, the lattice distortion phenomenon corresponding to the relatively smaller atomic radius of Mg atoms occurs when the atomic radius of the atoms is replaced by the relatively larger atomic radius of Ga atoms, the larger quantity of Mg atoms are gathered in the gap region, large-scale dislocation and defects are further caused in the epitaxial film, and the risk of diffusing the quantum well region is increased due to the higher growth temperature and the closer distance between the Mg doping and the quantum well. Therefore, the growth temperature of the P-type insertion layer is lower than that of the multi-quantum well layer, the doping concentration of Mg close to the multi-quantum well layer is lower, and the influence of Mg diffusion to the multi-quantum well layer on the epitaxial quality is greatly reduced.

Drawings

Fig. 1 is a schematic structural diagram of an led epitaxial wafer according to the present invention;

fig. 2 is a flowchart of a method for preparing an led epitaxial wafer according to the present invention;

fig. 3 is a flowchart of step S2 of the method for manufacturing a light emitting diode epitaxial wafer according to the present invention.

Detailed Description

The present invention will be described in further detail below in order to make the objects, technical solutions and advantages of the present invention more apparent.

Unless otherwise indicated or contradicted, terms or phrases used herein have the following meanings:

in the present invention, "preferred" is merely to describe embodiments or examples that are more effective, and it should be understood that they are not intended to limit the scope of the present invention.

In the invention, the technical characteristics described in an open mode comprise a closed technical scheme composed of the listed characteristics and also comprise an open technical scheme comprising the listed characteristics.

In the present invention, the numerical range is referred to, and both ends of the numerical range are included unless otherwise specified.

Under the condition of the same Ga/Mg ratio, the growth temperature of the multiple quantum well layer is higher than that of the P-type insertion layer, and the high temperature leads to low Mg doping efficiency. Under the condition of different doping concentrations, PN junction widths, namely tunnel widths, are different, and the probability of zener breakdown of the device is different. The zener breakdown probability increases exponentially with decreasing width. Zener breakdown typically occurs in PN junctions with high doping concentrations. The higher doping concentration narrows the PN junction tunnel width and reduces the probability of zener breakdown.

In order to solve the above problems, the present invention provides a light emitting diode epitaxial wafer, as shown in fig. 1, comprising a substrate 1, and a buffer layer 2, an undoped GaN layer 3, an N-type GaN layer 4, a multiple quantum well layer 5, a P-type insertion layer 6, an electron blocking layer 7, and a P-type GaN layer 8 sequentially stacked on the substrate;

the P-type insertion layer 6 includes an AlGaN layer 61, an Mg-doped AlGaN layer 62, and an Mg-doped GaN layer 63 sequentially stacked on the multiple quantum well layer 5;

the Al component content in the AlGaN layer 61 is higher than that in the Mg-doped AlGaN layer 62, and the Mg component content in the Mg-doped AlGaN layer 62 is lower than that in the Mg-doped GaN layer 63;

the growth temperature of the P-type insertion layer 6 is lower than that of the multiple quantum well layer 5.

The corresponding lattice distortion phenomenon can occur when the atoms with relatively smaller atomic radius replace the atoms with relatively larger atomic radius of the Ga atoms, and the larger quantity of Mg atoms are gathered in the gap area, so that large-scale dislocation and defects can occur in the epitaxial film, and the risk of diffusing the quantum well area by the Mg is increased due to the higher growth temperature and the closer distance between the Mg doping and the quantum well. Therefore, the growth temperature of the P-type insertion layer 6 is lower than that of the multi-quantum well layer 5, and the doping concentration of Mg near the multi-quantum well layer 5 is lower, so that the diffusion of Mg into the multi-quantum well layer 5 is greatly reduced, and the epitaxial quality is affected.

In one embodiment, the Al doping concentration in the AlGaN layer 61 is 3×10 ⁸ atoms/cm ³ ～7×10 ⁸ atoms/cm ³ The method comprises the steps of carrying out a first treatment on the surface of the The Al doping concentration in the Mg-doped AlGaN layer 62 is 1.5X10 ⁸ atoms/cm ³ ～3.5×10 ⁸ atoms/cm ³ . Preferably, the Al doping concentration in the AlGaN layer 61 is 4×10 ⁸ atoms/cm ³ ～6×10 ⁸ atoms/cm ³ The method comprises the steps of carrying out a first treatment on the surface of the The Al doping concentration in the Mg-doped AlGaN layer 62 is 2×10 ⁸ atoms/cm ³ ～3×10 ⁸ atoms/cm ³ . In one embodiment, the Al doping concentration in the AlGaN layer 61 gradually decreases from the multiple quantum well layer 5 in a direction away from the multiple quantum well layer 5. The doping concentration of Al in the P-type insertion layer is changed from high to low, so that the migration rate of electrons can be reduced, and hole injection caused by continuous high doping of Al components can be avoided.

In one embodiment, the Mg doping concentration in the Mg doped AlGaN layer 62 is 2×10 ¹⁹ atoms/cm ³ ～5×10 ²⁰ atoms/cm ³ The method comprises the steps of carrying out a first treatment on the surface of the The Mg doping concentration in the Mg-doped GaN layer 63 is 5×10 ²⁰ atoms/cm ³ ～8×10 ²¹ atoms/cm ³ . Preferably, the Mg doping concentration in the Mg doped AlGaN layer 62 is 3×10 ¹⁹ atoms/cm ³ ～4×10 ²⁰ atoms/cm ³ The method comprises the steps of carrying out a first treatment on the surface of the The Mg doping concentration in the Mg-doped GaN layer 63 is 6×10 ²⁰ atoms/cm ³ ～7×10 ²¹ atoms/cm ³ . In one embodiment, the Mg doping concentration in the Mg doped AlGaN layer 62 gradually increases, and gradually decreases from the AlGaN layer 61 in a direction away from the AlGaN layer 61. According to the invention, the doping concentration of Mg in the P-type insertion layer 6 is changed from low to high, so that the tunnel width of a PN junction generated by the GaN-based LED is wider, and the probability of zener breakdown is greatly reduced. PN junction with lower doping and wider tunnel width is easy to generate avalanche breakdown and has higher breakdown voltage, the reverse voltage of the GaN-based LED is obviously increased, and the luminous efficiency is obviously improved.

In one embodiment, the AlGaN layer 61 has a thickness of 5nm to 50nm, with exemplary thicknesses of 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm for the AlGaN layer 61; the thickness of the Mg doped AlGaN layer 62 is 30nm to 100nm, and exemplary thicknesses of the Mg doped AlGaN layer 62 are 40nm, 50nm, 60nm, 70nm, 80nm, 90nm; the thickness of the Mg doped GaN layer 63 is 20nm to 100nm, and exemplary thicknesses of the Mg doped GaN layer 63 are 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm.

In one embodiment, the growth temperature of the P-type insertion layer 6 is 750 ℃ to 800 ℃. The P-type insertion layer of the invention adopts a low-temperature growth temperature, and the low-temperature growth can not only avoid damaging the In component In the multi-quantum well layer, but also be beneficial to doping Mg atoms, and finally provide the luminous efficiency of the LED.

In one embodiment, during the growth process of the AlGaN layer 61, the Al source flow rate is gradually changed from 200scc to 250scc to 50scc to 100sccm; in the growth process of the Mg-doped AlGaN layer 62, the Mg source inlet flow rate is gradually changed from 0scc to 50scc to 1000scc to 1500sccm. By the growth method, the Mg doping concentration on one side close to the multi-quantum well layer is low, and the fact that Mg diffuses into the multi-quantum well layer to influence epitaxial quality is effectively prevented. Meanwhile, the low Mg doping concentration at one side close to the multi-quantum well layer can enable the wide PN junction tunnel width generated by the GaN-based LED, and the probability of zener breakdown is greatly reduced.

Correspondingly, the invention provides a preparation method of the light-emitting diode epitaxial wafer, as shown in fig. 2, comprising the following steps:

s1, preparing a substrate 1;

in one embodiment, the substrate base can be a sapphire substrate or SiO ₂ One of a sapphire composite substrate, a silicon carbide substrate, a gallium nitride substrate and a zinc oxide substrate; preferably, a sapphire substrate is selected. Sapphire is the most commonly used substrate material at present, and the sapphire substrate has the advantages of mature preparation process, low price, easy cleaning and processing and good stability at high temperature.

S2, a buffer layer 2, an undoped GaN layer 3, an N-type GaN layer 4, a multiple quantum well layer 5, a P-type insertion layer 6, an electron blocking layer 7 and a P-type GaN layer 8 are sequentially deposited on the substrate 1.

In one embodiment, as shown in fig. 3, step S2 includes the steps of:

s21, depositing a buffer layer 2 on the substrate 1.

Preferably, the prepared substrate is transferred into a PVD machine, and an AlN film is plated in a magnetron sputtering mode, wherein the thickness of the film is controlled to be 10-80 nm;

s22, depositing an undoped GaN layer 3 on the buffer layer 2.

Preferably, the pressure of the reaction chamber is raised to 150-300 torr, the temperature of the reaction chamber is 1100-1160 ℃, TMGa is introduced as Ga source, NH is introduced ₃ Is N source, N ₂ And H ₂ As carrier gas, the undoped GaN layer with the total thickness of 1-5 μm is grown.

S23, depositing an N-type GaN layer 4 on the undoped GaN layer 3.

Preferably, the temperature of the reaction chamber is controlled between 1000 ℃ and 1100 ℃, the pressure is controlled between 200torr and 400torr, TMGa is used as Ga source, and NH is introduced ₃ As N source, N ₂ And H ₂ As carrier gas, is introduced with SiH ₄ Providing N-type doping and growing to obtain an N-type GaN layer with the thickness of 2-4 mu m.

And S24, depositing a multi-quantum well layer 5 on the N-type GaN layer 4.

The multiple quantum well layer includes a plurality of quantum well layers and quantum barrier layers alternately stacked. Firstly, growing InGaN quantum well layer, controlling the temperature of a reaction chamber to be 820-900 ℃, controlling the growth pressure to be 100-150 torr, and introducing N ₂ As carrier gas, an N source, an In source and a Ga source are used for growing to obtain an InGaN layer; then the In source is turned off, and then H is introduced ₂ And (3) taking the rest MO sources as carrier gas, and controlling the temperature to be between 820 and 900 ℃ independently of the carrier gas, and continuing to grow to obtain the GaN quantum barrier layer. The quantum well layers and the quantum barrier layers are alternately grown to obtain a plurality of quantum well layers.

S25, depositing a P-type insertion layer 6 on the multiple quantum well layer 5.

Preferably, the growth temperature of the P-type insertion layer is 750-800 ℃; in the growth process of the AlGaN layer, the Al source inlet flow rate is gradually changed from 200scc to 250scc to 50scc to 100sccm; in the growth process of the Mg-doped AlGaN layer, the inflow flow of the Mg source is gradually changed from 0scc to 50scc to 1000scc to 1500sccm. The features of the P-type insertion layer are as described above, and are not described here again.

S26, depositing an electron blocking layer 7 on the P-type insertion layer 6.

Preferably, the temperature of the reaction cavity is controlled between 1000 ℃ and 1050 ℃, the pressure is 200torr to 400torr, and an N source, a Ga source, an Al source and an Mg source are introduced to grow the P-type AlGaN electron blocking layer.

S26, depositing a P-type GaN layer 8 on the electron blocking layer 6.

Preferably, the temperature of the reaction cavity is controlled between 1000 ℃ and 1050 ℃, the pressure is 200torr to 400torr, and an N source, a Ga source and an Mg source are introduced to grow the P-type GaN layer. The total thickness of the AlGaN electron blocking layer and the P-type GaN layer is 100 nm-800 nm.

Correspondingly, the invention further provides an LED, and the LED comprises the LED epitaxial wafer. The photoelectric efficiency of the LED is effectively improved, and other items have good electrical properties.

The invention is further illustrated by the following examples:

example 1

The embodiment provides a light-emitting diode epitaxial wafer, which comprises a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a P-type insertion layer, an electron blocking layer and a P-type GaN layer which are sequentially laminated on the substrate;

the P-type insertion layer comprises an AlGaN layer, an Mg-doped AlGaN layer and an Mg-doped GaN layer which are sequentially laminated on the multiple quantum well layer;

the average Al doping concentration in the AlGaN layer is 5 multiplied by 10 ⁸ atoms/cm ³ The method comprises the steps of carrying out a first treatment on the surface of the The average doping concentration of Al in the Mg-doped AlGaN layer is 2.5X10 ⁸ atoms/cm ³ 。

The average doping concentration of Mg in the Mg-doped AlGaN layer is 1 multiplied by 10 ²⁰ atoms/cm ³ The average doping concentration of Mg in the Mg-doped GaN layer is 1 multiplied by 10 ²¹ atoms/cm ³ 。

The Al doping concentration in the AlGaN layer gradually decreases, and the Al doping concentration gradually decreases from the multiple quantum well layer to a direction away from the multiple quantum well layer. The Mg doping concentration in the Mg-doped AlGaN layer gradually increases, and gradually decreases from the AlGaN layer to a direction away from the AlGaN layer.

The growth temperature of the AlGaN layer is 750 ℃; the growth temperature of the Mg-doped AlGaN layer is 750 ℃; the growth temperature of the Mg-doped GaN layer is 750 ℃; the growth temperature of the multiple quantum well layer is 880 ℃.

Example 2

The present embodiment provides a light emitting diode epitaxial wafer, which is different from embodiment 1 in that: the growth temperature of the AlGaN layer is 760 ℃; the growth temperature of the Mg-doped AlGaN layer is 780 ℃; the growth temperature of the Mg-doped GaN layer is 790 ℃. The remainder was the same as in example 1.

Example 3

The present embodiment provides a light emitting diode epitaxial wafer, which is different from embodiment 1 in that: the average Al doping concentration in the AlGaN layer is 7 multiplied by 10 ⁸ atoms/cm ³ The method comprises the steps of carrying out a first treatment on the surface of the The average doping concentration of Al in the Mg-doped AlGaN layer is 3.5X10 ⁸ atoms/cm ³ The method comprises the steps of carrying out a first treatment on the surface of the The average doping concentration of Mg in the Mg-doped AlGaN layer is 5 multiplied by 10 ²⁰ atoms/cm ³ Average doping of Mg in the Mg-doped GaN layerThe concentration is 8 multiplied by 10 ²¹ atoms/cm ³ . The remainder was the same as in example 1.

Comparative example 1

This comparative example is different from example 1 in that no P-type insertion layer is provided, and an electron blocking layer, a P-type GaN layer, is directly deposited after the multiple quantum well layer. The remainder was the same as in example 1.

Comparative example 2

The comparative example provides a light-emitting diode epitaxial wafer, which comprises a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a P-type insertion layer, an electron blocking layer and a P-type GaN layer which are sequentially laminated on the substrate;

the P-type insertion layer comprises an AlGaN layer, an Mg-doped AlGaN layer and an Mg-doped GaN layer which are sequentially laminated on the multiple quantum well layer;

and the Al doping concentration and the Mg doping concentration are unchanged in the growth process of the P-type insertion layer.

The average Al doping concentration in the AlGaN layer is 5 multiplied by 10 ⁸ atoms/cm ³ The method comprises the steps of carrying out a first treatment on the surface of the The average doping concentration of Al in the Mg-doped AlGaN layer is 5 multiplied by 10 ⁸ atoms/cm ³ 。

The average doping concentration of Mg in the Mg-doped AlGaN layer is 1 multiplied by 10 ²⁰ atoms/cm ³ The average doping concentration of Mg in the Mg-doped GaN layer is 1 multiplied by 10 ²⁰ atoms/cm ³ 。

The growth temperature of the AlGaN layer is 750 ℃; the growth temperature of the Mg-doped AlGaN layer is 750 ℃; the growth temperature of the Mg-doped GaN layer is 750 ℃; the growth temperature of the multiple quantum well layer is 880 ℃.

The light emitting diode epitaxial wafers prepared in examples 1 to 3 and comparative examples 1 to 2 were prepared into 10×24mil chips using the same chip process conditions, 300 LED chips were extracted, and the photoelectric properties of the chips were tested, and specific test results are shown in table 1.

TABLE 1 results of Performance test of LEDs from examples 1-3 and comparative examples 1-2

From the above results, the light-emitting efficiency, antistatic capability and reverse voltage of the light-emitting diode epitaxial wafer provided by the invention are obviously improved, the influence of the high-temperature P-type coating on the multiple quantum well layer is effectively reduced, and the light-emitting efficiency of the GaN-based light-emitting diode is improved.

While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.

Claims (10)

1. The light-emitting diode epitaxial wafer is characterized by comprising a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a P-type insertion layer, an electron blocking layer and a P-type GaN layer which are sequentially laminated on the substrate;

the P-type insertion layer comprises an AlGaN layer, an Mg-doped AlGaN layer and an Mg-doped GaN layer which are sequentially laminated on the multiple quantum well layer;

the Al component content in the AlGaN layer is higher than that in the Mg-doped AlGaN layer, and the Mg component content in the Mg-doped AlGaN layer is lower than that in the Mg-doped GaN layer;

the growth temperature of the P-type insertion layer is lower than that of the multiple quantum well layer.

2. The light-emitting diode epitaxial wafer of claim 1, wherein the Al doping concentration in the AlGaN layer is 3 x 10 ⁸ atoms/cm ³ ～7×10 ⁸ atoms/cm ³ ；

The Al doping concentration in the Mg-doped AlGaN layer is 1.5X10 ⁸ atoms/cm ³ ～3.5×10 ⁸ atoms/cm ³ 。

3. The light-emitting diode epitaxial wafer of claim 1, wherein the Mg doping concentration in the Mg-doped AlGaN layer is 2 x 10 ¹⁹ atoms/cm ³ ～5×10 ²⁰ atoms/cm ³ ；

The Mg doping concentration in the Mg-doped GaN layer is 5 multiplied by 10 ²⁰ atoms/cm ³ ～8×10 ²¹ atoms/cm ³ 。

4. The light-emitting diode epitaxial wafer according to claim 1, wherein the Al doping concentration in the AlGaN layer gradually decreases from the multiple quantum well layer to a direction away from the multiple quantum well layer.

5. The light-emitting diode epitaxial wafer of claim 1, wherein the Mg doping concentration in the Mg-doped AlGaN layer gradually increases and gradually decreases from the AlGaN layer in a direction away from the AlGaN layer.

6. The light-emitting diode epitaxial wafer of claim 1, wherein the AlGaN layer has a thickness of 5nm to 50nm;

the thickness of the Mg doped AlGaN layer is 30 nm-100 nm;

the thickness of the Mg doped GaN layer is 20 nm-100 nm.

7. The light-emitting diode epitaxial wafer of claim 1, wherein the P-type insertion layer has a growth temperature of 750 ℃ to 800 ℃.

8. The light-emitting diode epitaxial wafer of claim 1, wherein in the growth process of the AlGaN layer, the Al source inlet flow rate is gradually changed from 200scc to 250scc to 50scc to 100sccm;

in the growth process of the Mg-doped AlGaN layer, the inflow flow of the Mg source is gradually changed from 0scc to 50scc to 1000scc to 1500sccm.

9. A method for preparing the light-emitting diode epitaxial wafer according to any one of claims 1 to 8, comprising the steps of:

s1, preparing a substrate;

s2, sequentially depositing a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, a P-type insertion layer, an electron blocking layer and a P-type GaN layer on the substrate;

the P-type insertion layer comprises an AlGaN layer, an Mg-doped AlGaN layer and an Mg-doped GaN layer which are sequentially laminated on the multiple quantum well layer;

the Al component content in the AlGaN layer is higher than that in the Mg-doped AlGaN layer, and the Mg component content in the Mg-doped AlGaN layer is lower than that in the Mg-doped GaN layer;

the growth temperature of the P-type insertion layer is lower than that of the multiple quantum well layer.

10. An LED, characterized in that the LED comprises a light emitting diode epitaxial wafer according to any one of claims 1 to 8.